Greywater and pipes giong through concrete slab

Hello Art,

Thanks for taking the time to answer questions about Grey Water. I've been interested in looking at using Gray Water here at our property for a long time. The main reason I haven't gone into it yet is that the house we bought was already built and most of the plumbing pipes are passed through and then under the concrete slab to our septic tanks. The current plumbing doesn't differentiate between gray water and black water, so all gets mixed together.

I've thought of a few ways to get it done, but it feels like it would require too much work even though the gain is huge. Some of the ways would be to open up the foundation at the area where gray/black water are mixed (anywhere we have a toilet) and add a second set of pipes for the black water. This way, these new pipes that would now only carry black water would find their way out via the walls and I would pipe them on the current septic system. While using the previous black/gray water pipes to only carry gray water from now on to the garden... My concern with this approach is whatever new pipes that will carry the black water only would have to never go higher than being on the concrete slab, or otherwise gravity will not work to carry the water out (i.e. if you have to go over a door frame). So the path for those pipes could be quite interesting depending on how the house is divided. Am I over thinking this and making it more complicated than it really is?

There must be an easier, faster and less expensive way to get this done? I have 3 toilets in the house (2 on the first floor with stained concrete as the floor and one on the second floor).

Thanks for any input. I'd love to find an easier way to move forward and use that precious resource properly.

Cheers

Jan

I suppose you must have already discarded the idea of simply putting in composting toilets and having the septic tanks pumped.. over time the septic system would approach greywater clean and the effort would be minimal on your part..... You've seen Joe Jenkins models, right? No bank breaking needed either.... best as always... ttyl

Jan,

I like Mj's suggestion--radical, in the sense of going to the root of the problem.

Apart from that:

• Greywater reuse does not make sense in every context. Sometimes it is more trouble than it is worth...hard as that may be to accept
• You can safely forget about jackhammering up your slab and running new toilet plumbing (see previous bullet)
• Go for the laundry--that's usually easy to get. See our Laundry to Landscape page (and the fabulous sexy new two page laundry to landscape *centerfold* in the 6th edition Create an Oasis with Greywater
• Have a plumber or greywater installer case out the showers baths, kitchen sinks near exterior walls and on the second floor and see if any diversion is worthwhile...too hard to explain with a keyboard how this is determined, but sometimes you can get at plumbing by an exterior wall
• Put resources and energy into more efficient fixtures and more efficient habits...likely to have higher savings at lower cost than doing greywater with water hog fixtures and average habits.

Good luck!

Art

Thanks so much Mj, I really love your idea and sounds most simple for sure. So simple that it never crossed my mind LOL.

Thanks also Art for taking the time to share your knowledge. I definitely see a huge benefit in a dry area like here to preserve all the water I can. Taping into the wash water would be easy, thanks for the idea.

Cheers

Jan

I have often thought of digging under the slab to get to my shower drain and then connecting it to 2 1000 gallon plastic septic tanks. The first one would be filled with gravel to filter the water, hair etc. This would drain into the second one that would have a float pump in it to pump out the water to the trees and the lawn. (Did I mention I live in Oklahoma, where we've been, until recently, in a extreme drought for 5 years). Cost and TIME right now are my limiting factors.

Getting to using a USED septic tank to contain grey water....I would have serious concern using this water to water anything. As a nurse practitioner, I have seen the problems the bacteria E. coli (present in all feces) can cause a person. This could be transmitted to anything the water hits. I doubt (please correct me) that a USED septic tank would ever get rid of the E. coli. Maybe after several several years it would be undetectable. Any research out there on this?

Barry Chapman

Hello Barry,

I definitely see that a concrete tank (my septic tanks are 3 big concrete tanks) could keep pathogens around forever since they contained black water at some point. If I were ever to use that water on my garden after not flushing any more black water, I would at a very minimum get the tanks emptied first and also make sure all 3 tanks get ozonated for let's say 30 min before sending any water to the garden. An ozonator is cheap to run and will take everything out like. Just a thought I wanted to share in case others are also wondering how to get it done with some levels of sanitation and safety.

Cheers

Jan

See:

Error: storage of greywater

Note especially the photo of the greywater to blackwater conversion tank...